Isshiki & Partners

What Isshiki & Partners does

Isshiki & Partners is a Tokyo-based boutique law firm founded in June 2021 by Taro Isshiki and Kazuo Isshiki, specializing in cross-border dispute resolution and intellectual property matters between Japan and the United States. The firm offers three integrated practice areas: Litigation & Dispute Resolution (Japanese litigation, U.S. litigation support, and international arbitration under ICC and JCAA rules), Intellectual Property (strategy, disputes, licensing, prosecution, and due diligence), and Corporate & Commercial Advisory (M&A, joint ventures, compliance, internal investigations, and cross-border data/contracts).

The firm's competitive position rests on a senior-heavy bench drawn from top global law firms and in-house roles: Managing Partner Taro Isshiki spent 13 years at Morrison & Foerster; partner Yukio Nagasawa is a former judge who handled 2,000+ IP cases at the Tokyo District Court, Tokyo High Court, and Supreme Court of Japan; partner Yaeko Hodaka joined from Baker McKenzie; partner Yukako Wagatsuma joined from PwC Legal Japan; and partner Hiromi Furushima joined in June 2025 from Novartis Pharma K.K. where she served as Corporate Officer, General Counsel and Head of Legal & IP. The firm operates within the Isshiki Group alongside Isshiki Patent & Trademark Firm (20 patent attorneys, 50+ years of history), enabling integrated legal-plus-technical IP coverage under a shared Mita, Minato-ku office.

Revenue is generated through traditional professional services fees (hourly rates, fixed fees, and retainers) on cross-border mandates sourced via direct client engagement with multinationals and Japanese corporates, plus referrals from international law firms. Target segments are global enterprises with Japan exposure and Japanese companies with international operations. The firm pursues content-driven demand generation via its Insight Series publications, professional seminars, Nikkei media commentary, and academic lectures at Keio Law School. In 2022 it was recognized by Asian Legal Business as one of the Top 10 Japan Law Firms to Watch.

Name

Isshiki & Partners

Legal name

Isshiki & Partners

Website

https://isshiki-law.com

Company type

Private

Founded year

2021

Operating status

Operating

Headcount range

1–10 employees

Short description

Isshiki & Partners is a Tokyo-based boutique law firm founded in 2021 that provides cross-border litigation, intellectual property, and corporate/M&A advisory to multinational corporations and Japanese companies with international operations, leveraging a senior bench drawn from top global firms.

Ownership category

akta.pro rank

Product category

Cross-Border Legal Services

NAICS

Offices of Lawyers (541110)

SIC

Services-Legal Services (8111)

akta.pro primary industry

IP Search, Watch & Competitive Intelligence (BPAHAMAI)

akta.pro secondary industries

IP Filing, Annuities & Renewals Administration (BPAHAMAJ), Strategic Partnerships, Alliances & JVs Advisory (BPAHADAI), Corporate Development & Strategic Partnerships Advisory (JVs, Alliances, Carve-outs) (BPAHAOAG), IP & Patent Information Publishing (Patent/Litigation Analytics, Prior Art) (MPAJACAK)

Keywords

• Cross-border litigation
• Intellectual property law
• International arbitration
• Patent prosecution
• Corporate legal advisory

Headquarters

HQ city

Tokyo

HQ country

Japan

HQ region

Asia

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Marketing or Sales, Infrastructure, Technology or R&D

Revenue model

1. Legal Services Fees: Professional legal services billed on hourly rates, fixed fees for specific matters, or retainer arrangements for ongoing client relationships. Services include litigation representation, corporate advisory, IP strategy, and transaction support.

Go-to-market motion1 record

Distribution channels2 records

Marketing channels5 records

Core offering

Isshiki & Partners is a Tokyo-based boutique law firm providing cross-border legal services focused on dispute resolution, intellectual property, and corporate and commercial advisory. The firm represents clients in Japanese litigation, U.S. litigation support, and international arbitration, and delivers integrated IP services ranging from patent/trademark prosecution and IP strategy to licensing, disputes, and due diligence, supported by its affiliation with Isshiki Patent and Trademark Firm.

Product overview

Isshiki & Partners is a Tokyo-based law firm offering legal services as a single unified practice. The firm's core offerings span three main areas: Litigation & Dispute Resolution (Japanese litigation, U.S. litigation support, and international arbitration), Intellectual Property (IP strategy, disputes, licensing, due diligence, and patent/trademark prosecution), and Corporate & Commercial Matters (advisory, transactions, compliance, and data protection). The firm collaborates closely with its affiliate, Isshiki Patent & Trademark Firm, to provide integrated legal and technical support. Additionally, the firm publishes the Insight Series, a collection of educational articles on cross-border legal topics.

Differentiator

Problem solved

Functional benefit

Products and services

• Litigation and Dispute Resolution Services

Segments3 records

Ideal customer profiles3 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Partnerships

Two partnerships are on record, tiered minor and core.

• Rothwell, Figg, Ernst & Manbeck LLPminorStrategic or Co-development Partner · 20 October 2016Co-organized an IP seminar titled 'The Current Status of Patent Protection in the United States and Its Impact on the IP Strategies of Japanese Companies' with Isshiki International Law Office and Isshiki & Co.
• Isshiki Patent & Trademark FirmcoreStrategic or Co-development Partner · 9 May 2009Affiliate firm sharing the same office building. Isshiki Patent & Trademark Firm has 20+ patent attorneys with 50+ years of experience. Provides integrated legal and technical support across full IP spectrum including patent/trademark prosecution, coordinated with litigation services. Managing Partner Kazuo Isshiki's father serves as managing partner of the patent firm.

Scale indicators8 records

Recent moves8 records

Expansion highlights5 records

Broad incumbents

• Paul Hastings: Global firm with a Tokyo office (and prior employer of Kazuo Isshiki); comparable as a competing cross-border corporate/IP platform serving multinationals operating in Japan.
• Ropes & Gray: U.S. firm with a focused Tokyo IP and cross-border practice; relevant because it serves the same multinational IP clients from a Japan base and competes for U.S.–Japan litigation coordination mandates.
• Baker McKenzie: Global firm with a major Tokyo office and cross-border IP/M&A practice; comparable because it both competes with and is a former employer/feeder firm for Isshiki's partners, and pursues the same multinational clients.
• Mori Hamada & Matsumoto: Major Tokyo-headquartered full-service law firm with strong cross-border M&A and IP capabilities; comparable because it serves the same Japanese corporates and multinational clients on cross-border transactions and disputes.
• Morrison & Foerster: Global firm with a leading Japan practice and the prior employer of Isshiki's managing partner; directly relevant because it competes for the same Japan–U.S. cross-border IP mandates and houses several of Isshiki's referral contacts.
• Nishimura & Asahi: Japan's largest law firm with a top-tier cross-border IP and dispute resolution practice; competes for the same multinational and Japanese corporate clients that Isshiki & Partners serves, but at much greater scale.
• Orrick Herrington & Sutcliffe: Global firm with a Tokyo office and prior employer of Kazuo Isshiki; relevant because it competes for the same cross-border dispute and technology mandates that Isshiki targets.

Direct peers

• Anderson Mori & Tomotsune: Tokyo-founded firm with strong U.S. and cross-border IP/dispute practice — among the most directly comparable Japanese law firms to Isshiki in niche, scale, and cross-border orientation.
• TMI Associates: Tokyo IP-specialized law firm with deep patent litigation and prosecution bench; closely comparable on the IP-heavy service mix and Japanese corporate client base that Isshiki targets.

Emerging players

• Rothwell, Figg, Ernst & Manbeck: U.S. IP boutique with documented cooperation history (joint seminar with Isshiki) on Japan–U.S. IP matters; a natural referral partner and comparable on niche patent litigation focus.

Market position

Strengths5 records

Weaknesses4 records

Competitive moat4 records

Key risks5 records

Key highlights6 records

Customer concentration

• LinkedInlinkedin.com/company/isshiki-partners

Revenue estimate

Valuation estimate

Number of profiles

Profiles9 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Isshiki & Partners